Manufacture of cutting elements having lobes

ABSTRACT

An apparatus for forming a cutting insert. The apparatus may include compression device having a first sleeve with a bore therein. The first sleeve may receive a substantially hollow can. A plurality of solid particulates may be positioned within the can, and a substrate material or other punch may also be positioned in the can. A forming device of the compression device may be located adjacent an end of the can in which the solid particulates are located. The forming device may include at least one protrusion extending from an inner surface thereof into the bore. The protrusion may be adapted to deform the can while also forming the plurality of solid particulates into a solid mass having one or more reliefs and one or more lobes therein.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/746,758, filed Dec. 28, 2012, and entitled“Cutting Element for Percussion Drill Bit,” which application isexpressly incorporated herein by this reference in its entirety.

BACKGROUND

In drilling a wellbore in a subterranean formation, such as for therecovery of hydrocarbons, a drill bit is connected to the lower end of adrill string that includes a plurality of drill pipe sections connectedend-to-end. The drill bit is rotated by rotating the drill string at thesurface and/or by actuation of downhole motors or turbines. With weightapplied to the bit from the drill string, the rotating drill bit engagesthe formation causing the drill bit to cut through the subterraneanformation by either abrasion, fracturing, or shearing action, therebyforming the wellbore.

Several types of drill bits are used in drilling operations, and mayinclude percussion hammer bits, roller cone bits, fixed cutter bits, anddrag bits. In drilling operations using percussion hammer bits, thedrill bit is mounted to the lower end of the drill string, and the drillstring moves the drill bit back and forth axially to impact theformation to crush, break, and loosen formation material. To facilitatesuch effect, multiple inserts or cutting elements may be disposed on aface of the drill bit to impact the formation and crush, break, andloosen the formation material. In order to promote efficientpenetration, the percussion hammer drill bit is “indexed” so that thecutting elements contact fresh formations for each subsequent impact.Indexing is achieved by rotating the percussion hammer drill bit aslight amount between each axial impact of the bit with the formation.In such operations, the mechanism for penetrating the formation is of animpacting nature, rather than shearing nature. The impacting androtating percussion hammer drill bit engages the formation and proceedsto form the wellbore along a predetermined path toward a target zone.

SUMMARY

In accordance with some embodiments of the present disclosure a methodfor forming a cutting insert is disclosed. The illustrative method mayinclude inserting solid particulates and a substrate material into asubstantially hollow can. The substrate material may include a baseportion and an extension portion. The substantially hollow can,substrate material, and solid particulates may be inserted into a boreof a sleeve, and the substantially hollow can may be engaged against aforming device having at least one protrusion. A force may be applied tothe substrate material within the substantially hollow can to deform thesubstantially hollow can while the solid particulates are therein, whilealso causing the solid particulates to become press-fit to an outersurface of the extension portion while within the substantially hollowcan.

In another embodiment, an apparatus for forming a cutting insert isdisclosed in accordance with some aspects of the present disclosure. Theapparatus may include a sleeve having a bore therein. The sleeve may bearranged and designed to receive a substantially hollow can and solidparticulates within the substantially hollow can. A forming device maybe located at a first end portion of the bore and can include at leastone protrusion extending into the bore. The protrusion may be arrangedand designed to deform the can while the solid particulates are therein.In some embodiments, the protrusion may deform the can and substratematerial, and form a layer of solid particulates on the deformedsubstrate material, during a single compressive cycle.

In another embodiment, a method for forming a cutting insert may includeinserting diamond particles into a deformable can. A punch may beinserted into the deformable can such that the diamond particles arebetween the punch and an interior surface of the can. The punch, can,and diamond particles may be inserted wholly or partially into acompression device, and a compressive force may be applied to the punchto cause a protrusion of the compression device to deform the can andthe punch such that a relief is formed in a deformed portion of thepunch, and the plurality of diamond particles form a substantially solidlayer press-fit to the deformed portion of the punch.

This summary is provided to introduce a selection of concepts that arefurther described below in the detailed description. This summary is notintended to identify key or essential features of the claimed subjectmatter, nor is it intended to be used as an aid in limiting the scope ofthe claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe various features and concepts of the presentdisclosure, a more particular description of certain subject matter willbe rendered by reference to specific embodiments which are illustratedin the appended drawings. These drawings depict example embodimentswhich are to scale for some, but are not drawn to scale for eachpossible embodiment. The drawings are not to be considered to belimiting in scope.

FIG. 1 is a side view of an illustrative percussion hammer drill bit,according to one or more embodiments of the present disclosure.

FIG. 2 is a bottom view of a bit face of the percussion hammer drill bitincluding a plurality of cutting elements, according to one or moreembodiments of the present disclosure.

FIG. 3 is a perspective view of a cutting element, according to one ormore embodiments of the present disclosure.

FIG. 4 is a perspective view of another cutting element, according toone or more additional embodiments of the present disclosure.

FIG. 5 is a side view of a cutting element following engagement with aformation, according to one or more embodiments of the presentdisclosure.

FIG. 6 is a side view of an illustrative cutting element, according toone or more embodiments of the present disclosure.

FIG. 7 is a perspective view of an illustrative cutting element havingthree lobes, according to one or more embodiments of the presentdisclosure.

FIG. 8-1 is a perspective view of another illustrative cutting elementhaving three lobes, according to one or more embodiments of the presentdisclosure.

FIG. 8-2 is a perspective view of another illustrative cutting elementhaving three lobes, according to one or more embodiments of the presentdisclosure.

FIG. 9 is a perspective view of an illustrative cutting element havingfour lobes, according to one or more embodiments of the presentdisclosure.

FIG. 10 is a perspective view of another illustrative cutting elementhaving four lobes, according to one or more embodiments of the presentdisclosure.

FIGS. 11-1 and 11-2 are perspective and cross-sectional views,respectively, of an illustrative cutting element, according to one ormore embodiments of the present disclosure.

FIGS. 12-1 and 12-2 are perspective and cross-sectional views,respectively, of another illustrative cutting element, according to oneor more embodiments of the present disclosure.

FIG. 13 is a perspective view of another illustrative cutting element,according to one or more embodiments of the present disclosure.

FIGS. 14-1 and 14-2 are perspective and cross-sectional views,respectively, of another illustrative cutting element, according to oneor more embodiments of the present disclosure.

FIGS. 15-1 and 15-2 are cross-sectional and perspective views,respectively, of another illustrative cutting element, according to oneor more embodiments of the present disclosure.

FIGS. 16-1 and 16-2 are cross-sectional and perspective views,respectively, of another illustrative cutting element, according to oneor more embodiments of the present disclosure.

FIG. 17 depicts an illustrative impact crater in a subterraneanformation as may be formed by a cutting element having three lobes,according to one or more embodiments of the present disclosure.

FIG. 18 depicts an illustrative impact crater in a subterraneanformation as may be formed by a cutting element having four lobes,according to one or more embodiments of the present disclosure.

FIG. 19-1 depicts a bit face of a percussion drill bit having aplurality of cutting elements coupled thereto, according to one or moreembodiments of the present disclosure.

FIG. 19-2 depicts a subterranean formation having a plurality of cracksformed therein after being contacted by the bit face shown in FIG. 19-1,according to one or more embodiments of the present disclosure.

FIG. 20-1 depicts a bit face of a percussion drill bit having aplurality of cutting elements coupled thereto, according to one or moreembodiments of the present disclosure.

FIG. 20-2 depicts a subterranean formation having a plurality of cracksformed therein after being contacted three times with the bit face shownin FIG. 20-1, according to one or more embodiments of the presentdisclosure.

FIG. 20-3 depicts another subterranean formation having a plurality ofcracks formed therein after being contacted three times with the bitface shown in FIG. 20-1, according to one or more embodiments of thepresent disclosure.

FIGS. 21 and 22 schematically depict a bit face of a percussion drillbit having a plurality of cutting elements coupled thereto, according toone or more embodiments of the present disclosure.

FIG. 23 schematically depicts a bit face of a percussion drill bithaving a plurality of cutting elements coupled thereto, with proximitylines illustrated between the most proximate cutting elements, accordingto one or more embodiments of the present disclosure.

FIG. 24 schematically depicts proximity lines between a generated pointand the most proximate cutting elements, according to one or moreembodiments of the present disclosure.

FIG. 25 schematically depicts an illustrative impact pattern for apercussion drill bit having a plurality of cutting elements coupled to abit face of the percussion drill bit, according to one or moreembodiments of the present disclosure.

FIG. 26 depicts another illustrative pattern for a percussion drill bithaving a plurality of cutting elements coupled to a bit face of thepercussion drill bit, according to one or more embodiments of thepresent disclosure.

FIG. 27 is a flowchart of an illustrative method for designing apercussion hammer bit, according to one or more embodiments of thepresent disclosure.

FIG. 28 depicts a bit face having a plurality of cutting elementscoupled thereto, according to one or more embodiments of the presentdisclosure.

FIG. 29 depicts a partial cross-sectional view of an illustrativeassembly for forming a shaped cutting insert, according to one or moreembodiments of the present disclosure.

FIG. 30 depicts a perspective view of an illustrative pressing assemblyfor forming a shaped cutting insert, according to one or moreembodiments of the present disclosure.

FIG. 31 depicts a cross-sectional side view of a pressing assembly forforming a shaped cutting insert, according to one or more embodiments ofthe present disclosure.

DETAILED DESCRIPTION

Embodiments disclosed herein generally relate to bits. Morespecifically, embodiments disclosed herein may relate to cutting insertsfor percussion hammer bits. More particularly still, embodimentsdisclosed herein may relate to cutting inserts having multiple lobes andwhich may be used in percussion hammer bits, and methods formanufacturing cutting inserts having multiple lobes.

FIG. 1 depicts a side view of an illustrative percussion hammer bit 10having a bit face 14 for impacting and breaking up a formation. Anexample of the bit face 14 is further illustrated in FIG. 2 whichdepicts the bit face 14 of the percussion hammer bit 10 having aplurality of cutting inserts 100 coupled thereto. Any number of cuttinginserts 100 may be coupled to, or otherwise disposed on, the bit face14, and the cutting inserts 100 may be arranged in any number ofmanners, configurations, patterns, and the like. Moreover, the cuttinginserts 100 themselves may have any number of different shapes, forms,constructions, or other characteristics.

An example of a cutting insert that may be used in connection with thepercussion hammer bit 10 of FIGS. 1 and 2 is shown in FIG. 3, whichprovides a perspective view of an illustrative cutting insert 100),according to one embodiment disclosed herein. The cutting insert 100 mayinclude a base portion 110 coupled to an extension portion 120. Alongitudinal axis L may extend through one or both of the base portion110 or the extension portion 120. As shown, the base portion 110 may becylindrical in some embodiments. With continued reference to FIGS. 1-3,the base portion 110 may be coupled to the bit face 14 of the bit 10. Insome embodiments, the extension portion 120 may be integral with thebase portion 110 and at least partially axially offset therefrom.

The extension portion 120 may include at least two lobes 122-1, 122-2 insome embodiments. The lobes 122-1, 122-2 may be integral with oneanother proximate the longitudinal axis L, and may extend radiallyoutward therefrom. The lobes 122-1, 122-2 of the cutting insert 100 mayhave a radial length D (as measured from the longitudinal axis L) and awidth W (as measured from opposing side walls 123 of the lobes 122-1,122-2 and in a plane generally perpendicular to the longitudinal axis L,or in a plane tangential to the lobes 122-1, 122-2). The radial length Dof the lobes 122-1, 122-2 may be less than or substantially equal to aradius of the base 110, the extension portion 120, or the cutting insert100. In some embodiments, the radial length D of the lobes 122-1, 122-2may be greater than the radius of the base 110.

The width W of the lobes 122-1, 122-2 may increase, decrease, or remainsubstantially the same moving outward from the longitudinal axis L alongthe radial distance D. As shown in FIG. 3, the width W may increase asthe radial distance from the longitudinal axis L increases, such thatthe width W may be greater proximate the outer radial edge of lobes122-1, 122-2 than proximate the longitudinal axis L. In otherembodiments, the greatest width W may be located at or near thelongitudinal axis L, or at a radial position of the lobes 122-1, 122-2that is between the longitudinal axis L and the outer radial edge of thelobes 122-1, 122-2.

The lobes 122-1, 122-2 may be circumferentially offset from one anotheraround the longitudinal axis L by one or more angles that may range fromabout 25° to about 240° in some embodiments. For instance, thecircumferential offset, or angle, between the lobes 122-1, 122 may rangefrom about 30°, about 45°, about 60°, or about 75° to about 90°, about1200, about 150°, about 180°, about 200°, or more. For example, theangle between center-lines of adjacent lobes 122-1, 122-2 may be betweenabout 50° and about 90°, between about 70° and about 10°, between about100° and about 140°, or between about 160° and about 200°. As shown, thelobes 122-1, 122-2 in FIG. 3 are circumferentially offset from oneanother by about 180°. In other embodiments, an angle between the lobes122-1, 122-2 may be less than about 25° or greater than about 240°.

A void or relief 128-1, 128-2 may be disposed between adjacent lobes122-1, 122-2. The reliefs 128-1, 128-2 may continue for an angle W_(R)around the extension portion 120, and between the sides 123 of the lobes122-1, 122-2. The angle W_(R) may range from about 10° to about 180° insome embodiments. More particularly, the angle W_(R) may range fromabout 15°, about 25°, about 30°, about 40°, about 50°, or about 60° toabout 75°, about 90°, about 120°, about 150°, or more. For example, theangle W_(R) may be between about 20° and about 40°, about 40° and about60°, between about 60° and about 80°, between about 80° and about 100°,between about 100° and about 120°, or between about 120° and about 140°.In other embodiments, the angle W_(R) may be less than about 30° orgreater than about 150°.

A height of the outer axial surface of the extension portion 120proximate the reliefs 128-1, 128-2 may, in some embodiments, vary withrespect to the base portion 110. As shown, the height of the outer axialsurface of extension portion 120 proximate the reliefs 128-1, 128-2 mayincrease moving radially inward. In other words, the height may begreater proximate the longitudinal axis L of the cutting insert 100 thanproximate the outer radial edge.

The lobes 122-1, 122-2 may extend axially away from the base portion110. An outer axial surface 127 (which may also be a top surface in theorientation shown in FIG. 3) of the lobes 122-1, 122-2 may therefore beoffset from an outer axial surface of the extension portion 120proximate the reliefs 128-1, 128-2 by a distance/height R_(R). Theheight R_(R) of the outer axial surface 127 of the lobes 122-1, 122-2may increase, decrease, or remain substantially constant along theradial length D and/or the width W of the lobes 122-1, 122-2 withrespect to the base portion 110. In some embodiments, the height of theouter axial surface 127, and thus the thickness of the lobes 122-1,122-2, may be generally constant moving outwardly from the longitudinalaxis L along at least a portion of the radial distance D. In someembodiments, the outer axial surface 127 and/or an outer axial surfaceof the extension portion within the reliefs 128-1, 128-3 may be convexlyor concavely curved, while in other embodiments, the outer axial surfaceof the extension portion 120 proximate the reliefs 128-1, 128-2 mayinclude a surface of the base portion 110. In some embodiments, and asshown in FIG. 3, the height R_(R) of the outer axial surface 127 of thelobes 122-1, 122-2 may gradually decrease proximate the outer radialedge of the lobes 122-1, 122-2, although the height R_(R) may vary inany number of manners along the radial distance D of the lobes 122-1,122-2.

For instance, in another embodiment, the height R_(R) of the outer axialsurface 127 of the lobes 122-1, 122-2 may increase moving inwardlytoward the longitudinal axis L along the radial distance D. In otherwords, the height of the outer axial surface 127 of the lobes 122-1,122-2 may be greater proximate the longitudinal axis L of the cuttinginsert 100 than proximate the outer radial edge of the extension portion120. As such, a crest portion 124 may be formed on the outer axialsurface 127 of the lobes 122-1, 122-2 proximate the longitudinal axis L.The axial distance between the outer axial surface 127 of the lobes122-1, 122-2 proximate the longitudinal axis (e.g., at the crest portion124) and the outer axial surface 127 of the lobes 122-1, 122-2 proximatethe outer radial edge may range from about 0.25 mm to about 12 mm insome embodiments. For instance, such an axial distance may range fromabout 0.5 mm, about 1 mm, about 2 mm, about 3 mm, or about 4 mm to about5 mm, about 6 mm, about 8 mm, about 10 mm, or more. For example, theaxial distance may be between about 0.5 mm and about 2 mm, between about1 mm and about 3 mm, between about 2 mm and about 4 mm, or between about3 mm and about 8 mm. In other embodiments, the axial distance may beless than about 0.25 mm or greater than about 12 mm.

As used herein, “crest portion” is used to refer to one or more portionsof the lobes (e.g., lobes 122-1, 122-2) of an extension portion havingan outer axial surface that is farthest from the base portion (i.e., atip or apex). A crest portion (e.g., crest portion 124) may act as acutting portion or contact portion of the cutting insert 100. In FIG. 3,the distance between the base portion 110 and the crest portion 124 isrepresented by R_(E), which may also represent a maximum thickness orheight of the extension portion 120 and/or lobes 122-1, 122-2.

The height of the outer axial surface 127 of the lobes 122-1, 122-2 maybe substantially constant along at least a portion of the width W, whilean interface or intersection 125 between the outer axial surface 127 andthe sides 123 may be chamfered, beveled, or tapered. In someembodiments, a plane of symmetry S may extend through each lobe 122-1,122-2 such that the side surfaces 123 of a particular lobe may be mirrorimages of one another. In another embodiment, however, the lobes 122-1,122-2 may not be symmetrical.

FIG. 4 is a perspective view of another illustrative cutting insert 200,according to one or more embodiments of the present disclosure. Thecutting insert 200 has a base portion 210 and an extension portion 220extending axially from the base portion 210. The extension portion 220may include two lobes 222-1, 222-2 which may intersect at or near alongitudinal axis L. The lobes 222-1, 222-2 may be generally similar tothe lobes 122-1, 122-2 described above with reference to FIG. 3;however, the width W of the lobes 222-1, 222-2 in FIG. 4 may decreasemoving radially outward from the longitudinal axis L along the radialdistance D. In some embodiments, the lobes 222-1, 222-2 may at theirwidest points have a width W less than about 10 mm, less than about 7mm, less than about 5 mm, less than about 4 mm, less than about 3 mm,less than about 2 mm, less than about 1 mm, less that about 0.5 mm, orless than about 0.25 mm (e.g., proximate the longitudinal axis L in FIG.4). When the lobes 222-1, 222-2 have a relatively smaller width W, thesurface area of the lobes 222-1, 222-2 contacting the formation may bereduced, thereby concentrating an impact force when the cutting insert200 is used in connection with a percussion hammer bit.

As shown, a height R_(R) of the lobes 222-1, 222-2 may gradually changealong the radial distance D. For instance, the height R_(R) of the lobes222-1, 222-2 may increase moving outwardly from the longitudinal axis Lalong the radial distance D. However, in other embodiments, the heightR_(R) of the lobes 222-1, 222-2 may gradually decrease moving outwardlyfrom the longitudinal axis L along the radial distance D. In still otherembodiments, the height Ra of the lobes 222-1, 222-2 may increase andthen decrease (or vice versa) moving outwardly from the longitudinalaxis L along the radial distance D. Further, the height R_(R) of thelobes 222-1, 222-2 may be designed with respect to the width W of thelobes 222-1, 222-2. In at least one embodiment, a ratio between theheight R_(R) of the lobes 222-1, 222-2 and the width W of the lobes222-1, 222-2 may be less than about 5:1, less than about 3:1, less thanabout 2.5:1, less than about 2:1, less than about 1.5:1 less than about1:1, or less than about 0.5:1.

FIG. 5 is a side view cutting profile 305 of an illustrative cuttinginsert 300 for contacting a subterranean formation 350, according to oneor more embodiments of the present disclosure. A cutting depth 330 inthe formation 350 may generally correspond to the height R_(R) of thelobes 322 in some embodiments. In some embodiments, the height R_(R) ofone or more lobes 322 may range from about 0.25 mm, about 0.5 mm, about0.75 mm, or about 1.0 mm to about 1.25 mm, about 1.5 mm, about 2.0 mm,about 3.0 mm, or more. For example, the height R_(R) of the lobes 322may be between about 0.25 mm and about 0.75 mm, between about 0.5 mm andabout 1.0 mm, or between about 0.75 mm and about 1.5 mm. In otherembodiments, the height R_(R) of the lobes 322 may be less than about0.25 mm or greater than about 3 mm.

The cutting depth 330 of the cutting insert 300 may refer to the depthwithin the formation 350 impacted or removed with each hammer, or blow,of the bit (see bit 10 of FIG. 1), as measured after the bit impacts theformation 350. In some embodiments, the cutting depth 330 may be lessthan the height R_(R) of the lobe 322. In at least one embodiment, theheight R_(R) of the lobe 322 may be about two times the cutting depth330. The cutting depth 330 may range in value depending on, for example,the formation 350 being drilled and the impact force applied by the bit.In some environments, after a single blow by the bit, the cutting insert300 may generate a cutting depth 330 ranging from about 0.05 mm, about0.1 mm, about 0.25 mm, or about 0.5 mm to about 0.75 mm, about 1 mm,about 1.5 mm, about 2 mm, or more. For example, the cutting depth 330may be between about 0.05 mm and about 0.5 mm, between about 0.05 mm andabout 0.25 mm, or between about 0.1 mm and about 0.75 mm. The cuttingdepth 330 may also be less than about 0.05 mm or greater than about 2 mmin some embodiments.

FIG. 6 illustrates a cutting profile 405 of a cutting insert 400,according to one or more embodiments. As shown, the cutting profile 405may have the cross-sectional shape of the cutting insert 400 withoutinclusion of at least some of the cutting surface geometry. Thus, theshape of the cutting profile 405 may not include reliefs formed betweenlobes in the extension portion 420.

As shown in FIG. 6, the cutting insert 400 may include a base portion410 and an extension portion 420. An outer surface of the extensionportion 420 may have a dome or partially spherical shape; however, inother embodiments, the outer surface of the extension portion 420 mayhave a conical, frustoconical, or other shape, or some combination ofthe foregoing. In the illustrated embodiment, the extension portion 420may have at least two reliefs 428-1, 428-2, and the outer axial surfaceof the extension portion 420 proximate the reliefs 428-1, 428-2 may beoffset from the outer surface of an adjacent lobe by a distance/heightR_(R). The profiles of the reliefs 428-1, 428-2 are shown in FIG. 6using dashed lines to represent the bases or outer surfaces of thereliefs 428-1, 428-2.

The height R_(E) from the base portion 410 to the crest portion 424 maybe defined in relation to a radius of the base portion R_(C). A ratio ofthe height R_(E) to the radius of the base portion R_(C) may be lessthan or equal to about 1:1, about 0.9:1, about 0.8:1, about 0.7:1, about0.6:1, or about 0.5:1. For example, the ratio of the height R_(E) to theradius of the base portion R_(C) may be between about 0.5:1 and about1:1, between about 0.6:1 and about 0.9:1, or between about 0.7:1 andabout 0.8:1. In other embodiments, the ratio of the height Re to theradius of the base portion R_(C) may be less greater than about 1:1 orless than about 0.5:1.

FIG. 7 is a perspective view of an illustrative cutting insert 500having three lobes 522-1, 522-2, 522-3, according to one or moreembodiments. As shown, the lobes 522-1, 522-2, 522-3 may becircumferentially offset from one another by about 120° around thelongitudinal axis L; however, this is merely illustrative and the lobes522-1, 522-2, 522-3 may be circumferentially offset at unequal angularintervals in other embodiments. The lobes 522-1, 522-2, 522-3 mayintersect with one another at or near a longitudinal axis L, which mayalso include a crest portion 524 in some embodiments. Optionally, thecrest portion 524 may be relatively flat when compared with thecurvature of the remaining portions of the extension portion 520. Forexample, the crest portion 524 may form a plane about perpendicular tothe longitudinal axis L. However, in other embodiments, the crestportion 524 may have a concave, convex, angled, or other type of surfacerelative to the longitudinal axis L and/or the base portion 510.

Each lobe 522-1, 522-2, 522-3 may include two opposing side surfaces523, as well as an outer axial surface 527. Each side surface 523 mayinterface or intersect the outer axial surface 527 at a junction such asintersection 525. The side surfaces 523 optionally mirror each other,such that a plane of symmetry S may extend along a radial distance D ofeach lobe 522-1, 522-2, 522-3 from the crest portion 524 to the outerradial edge of the extension portion 520.

A relief 528 may be formed between each adjacent set of lobes 522-1,522-2, 522-3. The extension portion 520 may have an outer axial surface529 proximate the relief 528, and potentially exposed therein. The outeraxial surface 529 and the relief 528 may be bordered by the sidesurfaces 523 of adjacent lobes 522-1, 522-2, 522-3. The side surfaces523 may intersect with the outer axial surface 529 at an angle. The sidesurfaces 523 may be substantially perpendicular relative to the outeraxial surface 529, although the side surfaces 523 may intersect with theouter axial surface 529 at an angle that is less than about 90° orgreater than about 90° in other embodiments. As with the intersectionbetween the side surfaces 523 and the outer axial surface 527 of thelobes 522-1, 522-2, 522-3, intersection angles may be measured withouttaking into account any curved, beveled, or other transition surface.

The axial height difference of the outer axial surface 527 from anuppermost to a lower most position (e.g., from the crest portion 524 toa position proximate the outer radial edge of the extension portion 520in FIG. 7) may range, in some embodiments, from about 0.5 mm, about 1mm, about 2 mm, about 3 mm, or about 4 mm to about 5 mm, about 6 mm,about 8 mm, about 10 mm, or more. For example, the axial heightdifference may be between about 0.5 mm and about 2 mm, between about 1mm and about 3 mm, between about 2 mm and about 4 mm, or between about 3mm and about 8 mm. In other embodiments, the axial height difference maybe less than about 0.5 mm or greater than about 10 mm.

FIG. 8-1 is a perspective view of another illustrative cutting insert600 having three lobes 622-1, 622-2, 622-3, according to one or moreembodiments. As shown, the lobes 622-1, 622-2, 622-3 may becircumferentially offset from one another (e.g., by about 120° aroundthe longitudinal axis L). While the lobes 522-1, 522-2, 522-3 in FIG. 7are each shown as having a generally constant width W along the radiallength D thereof, the width W of the lobes 622-1, 622-2, 622-3 in FIG.8-1 may vary moving outwardly from the longitudinal axis L along theradial distance D. More particularly, the width W of the lobes 622-1,622-2, 622-3 may decrease moving outwardly from the longitudinal axis Lalong the radial distance D.

Further, each lobe 622-1, 622-2, 622-3 may have two opposing sidesurfaces 623, and an outer axial surface 627, with each side surface 623intersecting the outer axial surface 627 at an intersection 625. Theside surfaces 623 may mirror each other, such that a plane of symmetry Smay extend along a radial distance D of each lobe 622-1, 622-2, 622-3,from the longitudinal axis L to the outer radial edge of the extensionportion 620. Additionally, each lobe 622-1, 622-2, 622-3 may extend aheight Ra that is the distance from the base portion 610 (or the outerradial surface of the base portion 610) to the outer axial surface 627of the lobes 622-1, 622-2, 622-3. The height R_(R) may vary along theradial distance D and/or along the width W of the lobes 622-1, 622-2,622-3.

The change in elevation of the outer axial surface 627 of the lobes622-1, 622-2, 622-3 between a crest portion 624 (e.g., proximate thelongitudinal axis L) and at a minimum elevation (e.g., proximate theouter radial edge of the extension portion 630) may range from about 0.5mm, about 1 mm, about 2 mm, about 3 mm, or about 4 mm to about 5 mm,about 6 mm, about 8 mm, about 10 mm, or more. For example, the change inheight or elevation distance may be between about 0.5 mm and about 2 mm,between about 1 mm and about 3 mm, between about 2 mm and about 4 mm, orbetween about 3 mm and about 8 mm.

As further shown in FIG. 8-1, the side surfaces 623 of the lobes 622-1,622-2, 622-3 may transition into the extension portion 620 at a locationaxially offset from the base portion 610. In the same or otherembodiments, the side surfaces 623 of the lobes 622-1, 622-2, 622-3 maytransition into the extension portion 620 at a location axially alignedwith the base portion 610. For instance, FIG. 7 illustrates the sidesurfaces 523 of the lobes 522-1, 522-2, 522-3 transitioning into thebase portion 510.

FIG. 8-2 is a perspective view of another illustrative cutting insert650 having three lobes 672-1, 672-2, 672-3, according to one or moreembodiments. Each of the lobes 672-1, 672-2, 672-3 may extend around aportion of the circumference of the cutting insert 650. The lobes 672-1,672-2, 672-3 may each extend from about 10°, about 20°, about 30°, about45°, or about 60° to about 90°, about 120°, about 150°, about 180°,about 210°, or more of the circumference of the cutting insert 650. Forexample, one or more of the lobes 672-1, 672-2, 672-3 may each extendaround the circumference of the cutting insert 650 between about 10° andabout 30°, between about 30° and about 60°, between about 60° and about90°, between about 90° and about 120°, between about 120° and about150°, between about 150° and about 180°, or between about 180° and about210°.

One or more lobes (e.g., lobe 672-3) may extend around a greater orlesser portion of the circumference of the cutting insert 650 thananother lobe (e.g., lobes 672-1, 672-2). As shown, the first and secondlobes 672-1 and 672-2 may illustratively extend around the circumferenceof the cutting insert 650 between about 10° and about 45°, while thethird lobe 672-3 may extend around between about 180° and about 210° ofthe circumference of the cutting insert 650. As should be appreciated bya person having ordinary skill in the art in view of the disclosureherein, the cutting insert 650 may include any number of lobes rangingfrom a low of about 1, about 2, or about 3 to a high of about 4, about6, about 8, about 10, or about 15, and any one or more of the lobes mayextend around a greater or lesser portion of the circumference of thecutting insert 650 relative to other lobes. Moreover, where the lobes672-1, 672-2, 672-3 may have different widths, the circumferentialoffsets between the lobes 672-1, 672-2, 672-3 as measured from thecentral axis of each lobe 672-1, 672-2, 672-3 may optionally vary.

FIG. 9 is a perspective view of an illustrative cutting insert 700having four lobes 722-1, 722-2, 722-3, 722-4, and FIG. 10 is aperspective view of another illustrative cutting insert 800 having fourlobes 822-1, 822-2, 822-3, 822-4, according to one or more embodimentsof the present disclosure. The lobes 722-1, 722-2, 722-3, 722-4 ofcutting insert 700, and the lobes 822-1, 822-2, 822-3, 822-4 of cuttinginsert 800, may optionally intersect to form a substantially flat crestportion 724, 824. In other words, the surface of the crest portion 724,824 may be generally planar, and optionally substantially perpendicularto the longitudinal axis L. The crest portions 724, 824 may transitioninto the outer axial surfaces of the respective lobes 722-1, 722-2,722-3, 722-4, 822-1, 822-2, 822-3, 822-4. According to otherembodiments, however, the crest portions 724, 824 may have a concave orconvex surface in relation to the base portion 710, 810 of the cuttinginsert 700, 800, or may be located at locations other than anintersection of the respective lobes 722-1, 722-2, 722-3, 722-4, 822-1,822-2, 822-3, 822-4 (e.g., along the length D of one or more lobes).

The width of the lobes 722-1, 722-2, 722-3, 722-4 on the cutting insert700 may be substantially the same moving radially outwardly from thelongitudinal axis L. The width of the lobes 822-1, 822-2, 822-3, 822-4on the cutting insert 800 may decrease moving radially outwardly fromthe longitudinal axis L. In other embodiments, the width of the lobes ofa cutting insert may increase moving radially outwardly and/or increaseand then decrease (or vice versa) moving radially outwardly from thelongitudinal axis. As further shown in FIG. 9, the side surfaces of thelobes 722-1, 722-2, 722-3, 722-4 may transition into the extensionportion 720 at a location axially aligned with the base portion 710. InFIG. 10, however, the side surfaces of the lobes 822-1, 822-2, 822-3,822-4 may transition into the extension portion 820 at a locationaxially offset from the base portion 810. The lobes 722-1, 722-2, 722-3,722-4 are thus shown as having a relatively more abrupt transition fromthe extension portion 720 as compared to the lobes 822-1, 822-2, 822-3,822-4 relative to the extension portion 820.

FIGS. 11-1 and 11-2 depict perspective and cross-sectional views,respectively, of an illustrative cutting insert 900 having a cuttingprofile 905 according to one or more embodiments. The cutting insert 900may have a base portion 910, and an extension portion 920 extending adistance R_(E) from the base portion 910 along a longitudinal axis L.The extension portion 920 may also include a plurality of lobes 922-1,922-2, 922-3, 922-4 intersecting at the crest portion 924. As shown inFIGS. 11-1 and 11-2, the crest portion 924 of the cutting insert 900 mayhave an outer axial surface that is convex with respect to the baseportion 910.

In the illustrated embodiment, the outer axial surfaces, or topsurfaces, of the lobes 922-1, 922-2, 922-3, 922-4 may extend generallydownwardly from the crest portion 924 toward the base portion 910 whenmoving radially outwardly from the longitudinal axis L. In someembodiments, the profile of the crest portion 924 may form a low-profileor blunt dome. By configuring the extension portion 920 of the cuttinginsert 900 to have both a relatively low distance/height R_(E) and acrest portion 924 forming a central tip, the cutting insert 900 may beutilized as if having a blunt profile and sharp profile at the sametime. For example, the low cross-sectional area of the crest portion 924may act as a sharp tip for penetrating a formation without causingtorque issues, while the blunt characteristics of the remainder of thelobes 922-1, 922-2, 922-3, 922-4 may reduce the force used to removeparts of the formation.

As used herein, a sharp profile may be used to refer to a crest portionor other portion of a cutting insert having a radius of curvature lessthan the radius of the base portion 910, and a blunt profile may referto a portion having a radius of curvature greater than or equal to thevalue of the radius of the base portion 910. In other embodiments, asshown in FIG. 3, the cutting insert 100 may have a cutting profile thatincludes a blunt profile. In other embodiments, such as shown in FIG.14-2 (described below) a cutting insert 1400 may have a cutting profilethat includes a sharp profile. In yet other embodiments, such as shownin FIGS. 12-2 and 13 (described below), a cutting insert may have acutting profile that includes a combination of blunt profiles and/orsharp profiles. Further, in some embodiments, the sharp profile mayinclude a radius of curvature that is less than about 80%, about 70%,about 60%, about 50%, about 40%, or about 30% of the radius of the baseportion. Moreover, in some embodiments, the blunt profile may have aradius of curvature that is greater than about 110%, about 120%, about130%, or about 140% of the radius of the base portion.

FIGS. 12-1 and 12-2 depict perspective and cross-sectional views,respectively, of another illustrative cutting element 1200, according toone or more embodiments. The cutting element 1200 may have a baseportion 1210, an extension portion 1220 extending a distance Re from thebase portion 1210 along or parallel to a longitudinal axis L of thecutting element 1200, and at least one relief 1260 formed in the outersurface of the extension portion 1220. As shown, the relief 1260 may beformed from two surfaces 1223-1, 1223-2 intersecting at an angle 6. Therelief may be formed between the crest portion 1224 and a remainingportion 1222 of the extension portion 1220, may have a substantiallycircular shape, and may extend circumferentially around the crestportion 1224. Thus, in contrast to some other embodiments illustratedherein in which the relief extended significantly in a radially outwarddirection, the relief 1260 illustrated in FIGS. 12-1 and 12-2 may extendprimarily circumferentially, and may exist as an annular relief betweenthe crest portion 1224, and the lobe (i.e., the remaining portion 1222)that extends around the circumference of the cutting element 1200. Therelief 1260 may have a height R_(R) measured from the lowest part of therelief 1260 (e.g., at the intersection of the two surfaces 1223-1,1223-2) to the top part of the remaining portion 1222 of the extensionportion 1220. Further, as shown in FIGS. 12-1 and 12-2, the extensionportion 1220 may have an outer radius larger than the radius of the baseportion 1210. In some embodiments, the cutting element 1200 may have amushroom-like shape.

As shown in FIG. 12-2, the cutting profile 1205 of the cutting element1200 may have a combination of blunt profiles, including a substantiallyspherical shape with a semi-round center (formed by the crest portion1224) encircled by the relief 1260. Such a cutting profile 1205 maycause communication between two cracks propagating from adjacent cratersformed by insert blows. In other embodiments, the cutting profile may beformed from multiple sharp profiles, or a combination of sharp and bluntprofiles.

FIG. 13 depicts a perspective view of another illustrative cuttingelement 1300, according to one or more embodiments. The cutting element1300 may have a base portion 1310, an extension portion 1320 extending adistance R_(E) from the base portion 1310 along a longitudinal axis L ofthe cutting element 1300, and at least one relief 1360 formed in theouter surface of the extension portion 1320. The relief 1360 may beformed from two surfaces 1323-1, 1323-2 intersecting at an angle, andmay extend around a crest portion 1324, between the crest portion 1324and the remaining portion of the extension portion 1320. As shown, theremaining portion of the extension portion 1320 may be a lobe 1322, andin some embodiments the relief 1360 and/or the lobe 1322 may have asubstantially circular shape.

Rather than extending a radial distance from the crest portion 1324 tothe base portion 1310 as described in embodiments herein (see, e.g.,FIG. 9), the lobe 1322 may extend circumferentially around the crestportion 1324 with the relief 1360 formed between the lobe 1322 and thecrest portion 1324. The relief 1360 may have a height R_(R) measuredfrom the lowest part of the relief 1360 (e.g., at the intersectionbetween the two surfaces 1323-1, 1323-2) to the uppermost portion of thelobe 1322. Further, the cutting element 1300 shown in FIG. 13 may have acombination of blunt and sharp profiles, including a blunt edge cuttingprofile and a sharp, conical, or frustoconical center profile.Particularly, the crest portion 1324 may have a sharp or substantiallyconical or frustoconical cutting profile in which the edges aretruncated to form a cutting element 1300 with elements of a conicalinsert and a blunt wedge. Such a cutting profile may contact and cut aformation using a first fracture mode of crushing and a second fracturemode of chipping.

According to embodiments of the present disclosure, cutting elements mayhave reliefs of various shapes, configurations, or orientations formedin the extension portion or cutting portion of the cutting element. Somereliefs may include groove-type reliefs are reliefs that are shapedsimilar to grooves (and thus may be referred to as “grooves”), which mayinclude a U-shaped, V-shaped, or other channel extending along a pathand defining a linear, tapered, or tear drop geometry. However, itshould be noted that reliefs according to other embodiments of thepresent disclosure may have other shapes and geometries and, thus, theterm “relief” may be used to refer broadly to relief shapes andgeometries, including groove shapes. According to some embodiments,reliefs may have various geometries, and each relief may have at leasttwo surfaces that intersect (e.g., a side surface with a base surface oranother side surface). In some embodiments, the at least two surfacesmay intersect at an angle; however, in other embodiments, the twosurfaces may form a continuous curve.

FIGS. 14-1 and 14-2 depict perspective and cross-sectional views,respectively, of another illustrative cutting element 1400, according toone or more embodiments. The cutting element 1400 may have a baseportion 1410, an extension portion 1420 extending a distance R_(E) fromthe base portion 1410, and a plurality of grooves 1460 formed in theextension portion 1420. In some embodiments, the base portion 1410 mayextend along or parallel to the longitudinal axis L. The grooves 1460may extend radially from a crest portion 1424, or cutting tip, to theouter radius/perimeter of the cutting element 1400 and longitudinallytoward the base portion 1410. The grooves 1460 may have a relief heightRa measured from the bottom of the groove 1460 to the top or outersurface of the surrounding extension portion 1420. The relief heightR_(R) may remain generally constant, or may vary along the length of thegroove 1460. Further, as shown, the grooves 1460 may have a width Wethat gradually decreases along the radial distance of each groove 1460,resulting in a plurality of lobes 1422 formed on either side of eachrelief that increase in width W in a direction extending towards thebase portion 1410 and the outer radius or perimeter of the cuttingelement 1400. In other embodiments, a groove may decrease in width in aradially outward direction, have a generally constant width, or havevarying sections of increasing or decreasing width.

Further, as shown in FIG. 14-2, the cutting profile 1405 of the cuttingelement 1400 may include a sharp profile. The conical shaped cuttingprofile may provide a high rate of penetration due to the sharpgeometry, but may also face high torque issues. By forming groove-shapedreliefs 1460 in the cutting portion of the cutting element 1400, thegrooves 1460 may relieve the high torque issues and also provide forefficient removal of crushed material after chip formation. Sharp,conical, and frustoconical profiles may include a crest portion 1424having a curvature thereon. In some embodiments, the radius of thecurvature may be between about 0.5 mm and about 5 mm. For example, insome embodiments, the radius of curvature may range from about 1.3 mm toabout 3.2 mm. In some embodiments, the curvature may include a variableradius of curvature, a portion of a parabola, a portion of a hyperbola,a portion of a catenary, a portion of a circle, a portion of an ellipse,a parametric spline, or some combination of the foregoing. Further, asshown in FIG. 14-2, sharp, conical, or frustoconical profiles mayinclude a cone angle α, which may be selected based on the particularformation to be drilled. In a particular embodiment, the cone angle αmay range from a low of about 30°, about 450, about 60°, or about 75° toa high of about 90°, about 105°, about 120°, about 135°, or more.

FIGS. 15-1 and 15-2 depict cross-sectional and perspective views,respectively, of an illustrative cutting element 1500, according to oneor more embodiments. The cutting element 1500 may have a base portion1510, an extension portion 1520, and a plurality of reliefs 1560. Theextension portion 1520 may extend longitudinally a distance R_(E) fromthe base portion 1510, while the reliefs 1560 may extend a radialdistance from a crest portion 1524 toward (and optionally fully to) anouter radius/perimeter of the cutting element 1500 or extension portion1520. Each relief 1560 may have one or more surfaces. In the illustratedembodiment, for instance, the reliefs 1560 may each include a bottomsurface 1569 intersecting at least two side surfaces 1523. The sidesurfaces 1523 may each intersect the bottom surface 1529 at an angle.Such angles may be the same, or may be different. As shown, threereliefs 1560 may be formed in the extension portion 1520. However, otherembodiments may include more or fewer than three reliefs 1560 formed inthe extension portion 1520 of the cutting element 1500, and optionallyextending radially from the crest portion 1524 toward the outer radiusof the cutting element 1500. Further, other geometries of reliefs 1560may be formed in the extension portion 1520 of the cutting element 1500,extending radially from the crest portion 1524 to the outer radius ofthe cutting element 1500.

FIGS. 16-1 and 16-2 depict cross-sectional and perspective views,respectively, of another illustrative cutting element 1600, according toone or more embodiments. The cutting element 1600 may have a baseportion 1610, an extension portion 1620 extending longitudinally adistance R_(E) from the base portion 1610, and a plurality of reliefs1660. The reliefs 660 may extend a radial distance from a crest portion1624 toward an outer radius of the cutting element 1600.

Each relief 1660 may have a bottom surface 1669 and at least two sidesurfaces 1623 intersecting the bottom surface 1669. In the illustratedembodiment, each side surface 1623 may intersect the bottom surface 1669at an angle. Each relief 1660 may have a substantially constant width,however, the illustrated embodiment depicts reliefs 1660 which may varyalong their lengths while extending in a radially outward direction. Thewidth may be measured across the bottom surface 1669 between twoopposite side surfaces 1623. For example, as shown, the reliefs 1660 mayhave a kernel shape, and the width of each relief may generally increasein a radially outward direction. However, according to otherembodiments, the width of the reliefs 1560 may decrease in a radiallyoutward direction, be substantially constant in a radially outwarddirection, or have a combination of increasing, decreasing, or constantwidth moving radially outward.

Further, the cutting elements shown in FIGS. 15-1 and 16-1 may haveconical cutting profiles 1505, 1605 with extended crest portions 1524,1624. More particularly, the crest portions 1524, 1624 may have convexouter surfaces relative to the respective base portion 1510, 1610, suchthat the outer surface may form an angle β. Where the outer surface ofthe crest portions 1524, 1624 are symmetric, the angle between the outersurface and the longitudinal axis may be β/2, and may be less than about45°. Such cutting profiles 1505, 1605 may provide a sharp nose or tip(formed by the convex-shaped crest), while the three or more grooves mayprovide a shear plane for sliding of powdered rock. Additionally, thecrest portion 1524, 1624 may facilitate the volume of formation removalafter plastic fracture.

While FIGS. 15-2 and 16-2 illustrate grooves 1560, 16601 which mayextend in a generally linear, radially outward direction, the grooves1560, 1660 or other reliefs may have other structures, geometries, andthe like. For instance, grooves or other reliefs may extend radiallyoutward along a curved, angled, helical, or other path. Moreover, whilethe grooves 1560, 1660 may extend fully to the outer perimeter of arespective cutting element 1500, 1600, other embodiments contemplate agroove 1560, 1660 which does not extend fully to the outer perimeter. Instill other embodiments, a lobe may not extend fully to the outerperimeter of the cutting element 1500, 1600, such as where acircumferential relief is formed at the outer perimeter of the cuttingelement 1500, 1600.

Cutting elements of the present disclosure may be formed of, forexample, tungsten carbide, tungsten carbide with a super-abrasivematerial surface, such as polycrystalline diamond (“PCD”) or cubic boronnitride (“PCBN”), and carbides, nitrides, borides, other matrixmaterials, or some combination of the foregoing.

During percussion or hammer drilling operations, a percussion drill bitmounted to the lower end of a drill string may impact the formation in acyclic fashion to crush, break and loosen the subterranean formationmaterial. The percussion cutting mechanism for penetrating the formationis of an impacting nature. A percussion drill bit may also rotate orindex between impacts of the percussion drill bit. In some embodiments,a slight rotational movement between each impact blow may be used inorder to avoid the cutting elements impacting the same portion of theformation as during an immediately prior impact.

FIG. 17 depicts an illustrative impact crater 1710 in a subterraneanformation 1700 as may be formed by a cutting element having three lobes(e.g., cutting element 500 in FIG. 7 or cutting element 600 in FIG. 8-1)according to one or more embodiments. The impact crater 1710 may have aborder 1712 (i.e., the outer radial edge) and the impression of threelobes 1722-1, 1722-2, 1722-3. The lobe impressions 1722-1, 1722-2,1722-3 shown may not extend to the border 1712 of the crater 1710;however, in some embodiments, the lobe impressions 1722-1, 1722-2,1722-3 may extend to the border 1712.

Each lobe impression 1722-1, 1722-2, 1722-3 may have an outer radialportion 1730. One or more cracks 1740 may formed in the formation 1700by the impact. The cracks 1740 may initiate or originate proximate theouter radial portion 1730 of the lobe impressions 1722-1, 1722-2, 1722-3and/or at the border 1712 of the impact crater 1710.

FIG. 18 depicts an illustrative impact crater 1810 in a subterraneanformation 1800 formed by a cutting element having four lobes (e.g.,cutting element 700 in FIG. 9 or cutting element 800 in FIG. 10),according to one or more embodiments. The impact crater 1810 in FIG. 18may have a border 1812 (i.e., the outer radial edge) and the impressionof four lobes 1822-1, 1782-2, 1822-3, 1822-4. The lobe impressions1822-1, 1782-2, 1822-3, 1822-4 shown may not extend to the border 1812of the crater 1810; however, in some embodiments, the lobe impressions1822-1, 1782-2, 1822-3, 1822-4 may extend fully to the border 1812. Insome embodiments, the border 1812 may not be formed, and an outer radialportion 1830 of each lobe impression 1822-1, 1782-2, 1822-3, 1822-4 mayform the radially outermost portion of the impact crater 1810.Regardless of whether a border 1812 is formed, one or more cracks 1840may form in the formation 1800 upon impact. Such cracks 1840 mayinitiate or originate proximate the border 1812 and/or the outer radialportions 1830 of the lobe impressions 1822-1, 1782-2, 1822-3, 1822-4.

According to embodiments of the present disclosure, cutting elements,such as the ones described herein, may be strategically positioned onthe face of the drill bit to induce cracks with a greater chance ofjoining or linking. For example, according to some embodiments, thecutting elements may be positioned/oriented on the face of the drill bitsuch that the areas having an increased likelihood of crack initiation(e.g., proximate the outer radial portion of a lobe impression and/orthe border of the impact crater), thereby increasing the likelihood ofcracks forming and joining during a single bit impact event. Accordingto other embodiments, the cutting elements may be positioned/orientedaround the face of the drill bit having a translational or rotationaloffset between adjacent cutting elements, such that crack initiationfrom the cutting elements in an impact event overlaps or is in closeproximity with the crack initiation from a subsequent impact event. Bytranslationally or rotationally offsetting the cutting elements alongthe face of the drill bit to provide cracks overlapping or adjacent tocracks from a previous impact event, increased crack joining may beachieved.

During percussion or hammer drilling operations, a percussion drill bitmounted to the lower end of a drill string may impact the formation in acyclic fashion to crush, break, and loosen formation material. Thepercussion drilling mechanism for penetrating the formation is of animpacting nature. A percussion drill bit may also have small or otherangular displacements per impact of the percussion drill bit (i.e., thepercussion drill bit may index and have a slight rotational movement foreach impact blow), in order to avoid the cutting elements from impactingthe same portion of the formation, or in the same orientation in thesame position, as during the previous impact.

FIG. 19-1 depicts an illustrative bit face 1900 of a percussion drillbit having a plurality of illustrative cutting elements 1902, and FIG.19-2 depicts a subterranean formation 1904 having a plurality ofillustrative cracks 1908 formed after being contacted with the bit face1900, according to one or more embodiments. The cutting elements 1902(e.g., cutting elements 700 in FIG. 9 or cutting elements 800 in FIG.10) may be positioned on the bit face 190X) of the bit such that theareas having an increased likelihood of crack initiation (e.g., theouter radial portions of the lobes) are aligned or proximate with eachother, thereby increasing the likelihood of cracks 1908 forming andjoining during a single bit impact event. As shown, the impact made byone bit blow on the subterranean formation 1904 may include plasticfailure at some or each impact crater 1906, and each impact crater 1906may have a shape corresponding to the contact surface of the cuttingelements 1902. The impact may also have a high degree of brittle failuredue to crack 1908 interlinking.

FIG. 20-1 depicts a bit face 2000 of a percussion drill bit havingillustrative cutting elements 2002, and FIGS. 20-2 and 20-3 depict asubterranean formation 2004 after being contacted with the bit face 2000three times, according to multiple embodiments of the presentdisclosure. The cutting elements 2002 may be spaced circumferentiallyaround the bit face 2000. In some embodiments, the bit face 2000 mayrotate between successive impacts, and the rotation of the bit face 2000may be about the same as the circumferential spacing between two or morecutting elements 2002, such that crack initiation from the cuttingelements 2002 in an impact event overlaps with or is in close proximitywith the crack initiation from a subsequent impact event. FIG. 20-2illustrates an example where impact sites 2006 corresponding to radiallyoutermost cutting elements 2002 overlap with each of three successiveimpacts. The impact made by the cutting elements 2002 includes plasticfailure shown by the impact craters 2006 of the cutting elements 2002and a high degree of brittle failure due to crack 2008 interlinking.

In the embodiment shown, the cutting elements 2002 may be positioned ina circumferential row around the gage or periphery of the bit face 2000.Optionally, at least some of the cutting elements 2002 may havediffering rotational offsets. FIG. 20-1, for instance, illustrates eachof eight cutting elements 2002 having a different rotational offsets. Asused herein, a rotational offset refers to a difference in alignmentwith respect to a selected direction between at least two cuttingelements. For example, a rotational offset shown in FIG. 20-1 may bemeasured with respect to alignment with a radial axis from the bit'srotational axis to the cutting element longitudinal axis. As shown, eachcutting element 2002 in a circumferential row may have an outer radialportion of a lobe positioned at an angle from a line 2005 intersectingthe rotational axis of the bit face 2000 and the longitudinal axis ofthe cutting element 2002. The angle of each cutting element 2002 mayvary (and may optionally incrementally increase going around acircumferential row). For example, a first cutting element 2007 may bealigned with its radial axis 2005 (i.e., have a 0° offset from itsradial axis), a second cutting element around the circumferential rowmay be rotationally offset from the first cutting element 2007 by θ, athird cutting element around the circumferential row may be rotationallyoffset by 2θ, and other cutting elements around the circumferential rowmay be rotationally offset by 3θ, 4θ, 5θ, 6θ, 7θ, or more. According toembodiments of the present disclosure, cutting elements 2002 may berotationally offset from their radial axes by an angle ranging from alow of about 0°, about 30°, about 60°, or about 90° to a high of about135°, about 180°, about 225°, about 270°, or more. Further, someembodiments may include cutting elements 2002 having a decreasingrotational offset and may include one or more circumferential rows, ormay include cutting elements 2002 having a rotational offset along anon-circumferential direction. In the illustrated embodiment, therotational offset is shown as increasing in a counterclockwise directionaround the outer circumferential row, with about every other cuttingelement 2002 from θ to 3θ and from 4θ to 7θ having an increased offset.In other embodiments, the rotational offset may increase incrementallybetween adjacent cutting elements, or in other manners.

FIG. 20-2 illustrates an example embodiment in which the rotation of thebit face 2000 (i.e., indexing) is about equal to the circumferentialspacing between two cutting elements 2002 on the outer circumferentialrow. As a result, with each successive impact, impact craters may beformed which overlap or nearly overlap. With differing rotationaloffsets, the lobes of each cutting element 2002 may form impact cratersoriented in different directions, which may increase plastic failure andlead to a high degree of brittle failure due to crack 2008 interlinking.

FIG. 20-3 illustrates another example embodiment in which one or moreimpacts may not be indexed to the circumferential offset betweenoutermost cutting elements 2002. In this embodiment, a second of threeimpacts may create intermediate impact craters 2006. Such impact cratersmay reduce the distance between impact craters, thereby facilitatingcrack 2008 interlinking. Rotational offsets of the cutting elements 2002may lead to orientations along lobes that align cracks in a directionlikely to increase crack interlinking.

FIGS. 21 and 22 schematically depict a bit face 2100 of a percussionhammer bit including a plurality of cutting elements 2110, according toone or more embodiments. As shown, the placement of the cutting elements2110 may be driven by the size and position of one or more fluidchannels 2120 formed between the cutting elements 2110. Spacing,strength constraints, and other factors which may cause smaller gapsbetween proximate cutting elements may also influence cutting element2110 placement.

As shown in FIG. 22, proximity lines 2130 may be determined betweenadjacent cutting elements 2110. The proximity lines 2130 may representthe most likely areas in which cracks will form in the rock formationduring a single impact event through brittle fracture. Crack inducementalong the proximity lines may be improved, leading to enhanced brittlefailure interlinking, by positioning cutting elements having at leastone crack initiation site on the bit face 2100, such that the crackinitiation sites are directed along the proximity lines. As describedabove, a crack initiation site may be located at a radius of curvaturealong a contact surface of the cutting element. In some embodiments,crack initiation sites may correspond to locations of lobes of a cuttingelement 2110.

According to embodiments of the present disclosure, the bit face 2100may have areas of relatively higher cutting element density and areas ofrelatively lower cutting element density. For example, as shown in FIGS.21 and 22, the bit face 2100 may have low cutting element density atareas of the bit face 2100 occupied by fluid channels 2120 andrelatively high cutting element density elsewhere on the bit face 2100.However, cutting element density may be relative to selected areas ofthe bit face 2100 and, thus, areas of low cutting element density mayalso be selected as particular regions between the channels 2120.

FIG. 23 schematically depicts a bit face 2300 including a plurality ofcutting elements 2310 disposed thereon and proximity lines 2330 betweenthe most proximate cutting elements 2310, according to one or moreembodiments. At least one low cutting element density region 2340 may beselected including an area of the bit face 2300 having a lower densityof cutting elements 2310 compared with another area of the bit face2300. For example, as shown in FIG. 23, an area of low cutting elementdensity 2340 may be selected as the region of the channels 2320 or as aregion between the channels. However, other regions of low cuttingelement density may be selected relative to a higher cutting elementdensity region on the bit face 2300. Upon selecting regions having lowcutting element density, at least one point 2350 may be generated in thelow cutting element density region 2340. The points 2350 may be close orcorrespond to the nearest point between neighboring cutting elements2310. Further, more than one point may be generated in a low cuttingelement density region 2340. For example, multiple points 2350 may begenerated in large areas of low cutting element density, such as in thechannel 2320 region, while one point 2350 may be generated in smallerareas of low cutting element density, such as between cutting elements2310 in the regions between the channels 2320.

FIG. 24 depicts proximity lines 2335 disposed between a generated point2350 and its most proximate cutting elements 2310, according to one ormore embodiments. Further inducement of cracks may be directed alongthese proximity lines 2335 to the generated points 2350, which may beareas of lesser crack formation due to the lower cutting element densityaround the generated points. Particularly, the cutting elements 2310 maybe positioned such that the outer radial portions of the lobes arepositioned along the proximity lines 2335 toward a generated point 2350.

FIG. 25 depicts an illustrative impact pattern 2500 for a percussion bithaving a plurality of semi-round top cutting elements dispersed aroundthe bit face, according to one or more embodiments. Particularly, impactcraters 2510 may be modeled in positions corresponding with therespective cutting element locations of on the bit face. The modelingmay be done by finite element analysis. The impact craters 2510 may bemodeled with a uniform input, simulating a uniform probability of crackinitiation around each cutting element to determine probabilitydensities of crack initiation. As shown, the areas having relativelylower cutting element density 2525 (compared with other areas of cuttingelement density) may have lower or improbable crack propagation, whilethe areas having relatively higher cutting element density 2526 may havehigher or more likely crack propagation.

By modeling areas of probability density of crack initiation, areas oflow probability density of crack initiation (compared with other areasof probability density of crack initiation) may be selected and targetedfor designing improved crack initiation impact patterns. For example,semi-round top cutting elements may be replaced with cutting elementshaving at least one crack initiation site. Cutting elements may also beoriented to place crack initiation sites toward one or more areas of lowprobability density of crack initiation.

FIG. 26 depicts an illustrative impact pattern 2600 for a percussion bithaving a plurality of cutting elements with crack initiation sites(e.g., lobes), according to one or more embodiments. The impact pattern2600) may be modeled with a combination of a uniform input and anincreased input, corresponding to appropriately placed and orientedcutting elements with crack initiation sites, such as increased input atthe crack initiation sites. Further inducement of cracks directed towardweak areas of cracks (e.g., areas of low probability density of crackinitiation) may be quantified by comparing the impact pattern 2600 shownin FIG. 26 (showing the impact from cutting elements having crackinitiation sites directed toward low probability densities of crackinitiation) with the impact pattern 2500 shown in FIG. 25 (showing theimpact from cutting elements without crack initiation sites). Forexample, as shown in FIG. 26, the impact pattern 2600 shows the impactcraters 2610 of cutting elements having crack initiation sites directedtoward low probability densities of crack initiation, such that theareas of low probability density of crack initiation 2625 may have ahigher or more likely crack propagation when compared to the same areasof low probability density of crack initiation 2525 shown in FIG. 25.

Additionally, placement and orientation of cutting elements with crackinitiation sites may be optimized by iteratively modeling and analyzingthe crack probability density. FIG. 27 depicts a flowchart of anillustrative method for designing a bit, according to one or moreembodiments. A placement pattern of the cutting elements on a hammer bitmay be modeled, as shown at 2710. One or more inputs may be applied tothe placement locations, as shown at 2720. For instance, a uniform inputmay be applied to the cutting element placement locations. A uniforminput may include, for instance, modeling each cutting elements as asemi-round top cutting element. The results may be analyzed, and areasof high and low probability density and the probability density gradientmay be distinguished, as shown at 2730.

One or more of the cutting element characteristics may be modified tosimulate preferential crack initiation sites, as shown at 2740. Forinstance, the location, position, or orientation of a cutting element orlobe of a cutting element may be modified. Inputs may then be applied tothe placement locations, as shown at 2750. For instance, a uniform inputand/or additional preferential inputs may be applied to the cuttingelement placement locations. Preferential inputs may include, forinstance, directional information about the orientation of lobes of acutting element, the number of lobes, the type of structure of lobes oran extension portion of a cutting element, and the like. The results maybe analyzed, and areas of high and low probability density and theprobability density gradient may be distinguished, as shown at 2760. Itmay then be determined whether the results are acceptable at 2770. Thisdetermination may be based upon any number of considerations. Forinstance, the determination may include a comparison of probabilitydensity plots, the minimization or maximization of probability density,the probability density gradient, other factors, or some combination ofthe foregoing. If the results are acceptable, the analysis may beconcluded, as shown at 2780. If the results are not acceptable, thecutting element placement, the number of cutting elements, theorientation of crack initiation inputs, the type of cutting elements, orthe like may be optimized by again modifying one or more cutting elementcharacteristics, as shown at 2740. Such inputs may then again be appliedat 2750, and the results analyzed at 2760 (e.g., by comparingprobability density plots, minimizing/maximizing probability density, orconsidering a probability density gradient). Various acts within themethod of FIG. 27 may repeat many times until an affirmative result isobtained at 2770.

FIG. 28 depicts a bit face 2800 having a plurality of cutting elements2802 disposed thereon, according to one or more embodiments. As shown,the cutting elements 2802 may each include at least three lobes, andeach lobe may include an outer radial portion 2803. At least oneadjacent pair of cutting elements 2802 may be placed on the bit face2000 with a plane of reflection 2810, 2811 being defined therebetween.The plane of reflection 2810, 2811 may be between adjacent cuttingelements 2802 in the same circumferential row (see plane 2810), or maybe between adjacent cutting elements 2802 in different circumferentialrows (see plane 2811). In another embodiment, a plane of reflection maybe between adjacent cutting elements 2802 not arranged in rows (notshown).

As shown, cutting elements 2820, 2822 are in the same circumferentialrow. More particularly, the cutting elements 2820 and 2822 may be in thegage or adjacent-to-gage circumferential row. In FIG. 28 the cuttingelements 2820, 2822 have the plane of reflection 2810 therebetween. Thefirst cutting element 2820 may include three lobes, and the secondcutting element 2822 may include four lobes, although in otherembodiments the cutting elements 2820, 2822 may have the same number oflobes. An outer radial portion 2821 of a lobe of the first cuttingelement 2820 may be rotated an amount 2825 about the longitudinal axisof the cutting element 2820 from the point of reflection of the outerradial portion 2823 of the nearest lobe of the second cutting element2822. The first outer radial portion 2821 may be rotated less than 50°from the point of reflection, less than 40° from the point ofreflection, less than 30° from the point of reflection, less than 20°from the point of reflection, less than 10° from the point ofreflection, or less than 5° from the point of reflection.

In some embodiments, the outer radial portion 2821 of the lobe of thefirst cutting element 2820 may be rotated 0° from the point ofreflection, such that the first and second outer radial portions 2821,2823 may be in mirrored positions across the plane of reflection 2810.For example, as shown in FIG. 28, an adjacent pair of cutting elements2830, 2832 has a plane of reflection 2811 therebetween. A lobe of thecutting element 2830 may have an outer radial portion 2831 that is in amirrored positioned from an outer radial portion 2833 of the nearestlobe of the cutting elements 2832. The cutting elements 2830, 2832 maybe in different circumferential rows. More particularly, for instance,the cutting element 2830 may be in the adjacent-to-gage row, and thecutting element 2832 may be in the gage row.

The placement and position of the cutting elements 2802 on the bit face2800 may be designed to increase the likelihood of crack joining. Forexample, according to some embodiments, a bit may be designed bymodeling a percussion hammer bit having a plurality of cutting elementson the bit face, determining proximity lines between adjacent cuttingelements, and modifying at least one cutting element to include acutting element having at least one crack initiation site. Each crackinitiation site may be located proximate an outer radial portion of alobe of the cutting element. As used herein, a proximity line is used torefer to a line which may be drawn in space from the radial center of acutting element to the radial center of an adjacent cutting element.

According to embodiments of the present disclosure, the amount ofbrittle failure generated during impact events of a percussion bit maybe increased by considering the percussion bit cutting structure as asystem, and positioning neighboring penetration elements (e.g., cuttingelements with lobes, semi-round tops, etc.) in such a way to maximizecrack joining caused in impact events. Increasing the amount of crackjoining, and thus brittle failure, may increase the rate of penetration(“ROP”) in the formation by removing more material through brittlefailure without increased penetration. Further, in embodiments havingcutting elements positioned with rotational and/or translational offsetsbetween adjacent penetration elements, an anti-tracking effect may beimparted on the bit, such that a penetration element in a subsequentimpact may not seat directly in an impact crater formed in the previousimpact, thus preventing wear due to tracking. Tracking may occur when apenetration element impacts and aligns with a previous impact crater,and may cause premature wear and failure of the bit body. Thus,premature wear and failure of a bit may be minimized using penetrationelement offsets.

FIG. 29 depicts a partial cross-sectional view of an illustrativeassembly for forming a shaped cutting element, according to one or moreembodiments of the present disclosure. The assembly illustrated in FIG.29 may, for instance, be used to form cutting elements having one ormore lobes and/or recesses, as described herein. The assembly in FIG. 29may include a substrate material 2900, a can 2920, and a forming deviceor button 3030 for forming a shaped cutting element. In someembodiments, a substrate material 2900 may include a base portion 2902and an extension portion 2904. The base portion 2902 may besubstantially cylindrical, and the extension portion 2904 may be taperedin some manner. For instance, the extension portion 2904 may be conical,frustoconical, partially spherical (i.e., a “semi-round top”), or havesome other shape. In at least some embodiments, the substrate material290) may include a carbide substrate.

In at least some embodiments, the can 2920 may be a hollow shell that isshaped and sized to correspond to, and receive, at least a portion ofthe substrate material 2900. For instance, the can 2920 may receive theextension portion 2904 therein, or may receive the extension portion2904 and/or at least some of the base portion 2902. The substratematerial 2900 may be inserted through an open end 2926 of the can 2920,and an inner surface 2922 of the can 2920 may be shaped and sized tocontact the outer surface 2906 of the substrate material 2900. Inanother embodiment, however, a small gap (e.g., less than 1 mm) mayexist between the inner surface 2922 of the can 2920 and the outersurface 2906 of the substrate material 2900.

The portion of the can 2920 that receives the extension portion 2904 ofthe substrate material 2900 may be generally conical, frustoconical, orpartially spherical (e.g., semi-spherical). In some embodiments, the can2920 may be made of one or more refractory materials, including metalssuch as niobium, molybdenum, tantalum, tungsten, rhenium, othermaterials, or combinations of the foregoing.

A plurality of solid particulates 2924 may be inserted into the can2920. Examples of solid particulates 2924 may be or include diamond,cobalt, tungsten, cubic boron nitride, other materials, or somecombination of the foregoing. In at least some embodiments, the solidparticulates 2924 may include highly abrasive or wear-resistantproperties. The solid particulates 2924 may have a cross-sectionallength ranging from about 0.5 μm to about 75 μm. For example, theaverage cross-sectional length may be from about 0.5 μm to about 5 μm,about 5 μm to about 10 μm, about 10 μm to about 20 μm to about 20 μm toabout 40 μm, about 40 μm to about 75 μm, or about 4 μm to about 30 μm.

Once the solid particulates 2924 have been inserted into the can 2920,the substrate material 2900 may be fully or partially inserted into thecan 2920. This may cause the solid particulates 2924 to be positionedbetween the extension portion 2904 of the substrate material 2900 andthe inner surface 2922 of the can 2920. The can 2920 may then be presseddown onto the forming device 3030, as described in greater detailherein. In another embodiment, prior to, or in lieu of, inserting thesubstrate material 2900 into the can 2920, a punch may be inserted intothe can 2920 and used to compact the solid particulates 2924. The punchmay, in some embodiments, have a shape similar to that of a substrate.The substrate material 2900 in FIG. 29 may therefore also represent apunch. In some embodiments, when a substrate material 2900 is insertedinto the can, compacting the solid particulates 2924 may cause the solidparticulates 2924 to form a solid mass that are press-fit or otherwisebonded to the outer surface of the extension portion 2904 (e.g., using ahigh-pressure, high-temperature process). When a punch other than thesubstrate material 2900 is used, the punch may form the solidparticulates 2924 into a solid mass, but the solid mass may beconfigured to be separable from the punch to allow a substrate material2900 to subsequently be inserted and bonded to the mass of solidparticulates 2924.

The forming device 3030 may include an inner surface 3032 that is shapedand sized to receive the curved outer surface 2906 of the substratematerial 2900 (or punch) and the can 2920. The inner surface 3032 of theforming device 3030 may have a radius of curvature ranging from about 1mm to about 50 mm or more in some embodiments. For instance, the innersurface 2032 of the forming device 3030 may have a radius from about 1mm, about 2 mm, about 5 mm, or about 10 mm to about 15 mm, about 20 mm,about 30 mm, about 40 mm, about 50 mm, or more. For example, the radiusof curvature may be from about 1 mm to about 5 mm, about 5 mm to about15 mm, about 10 mm to about 20 mm, about 15 mm to about 30 mm, about 20mm to about 40 mm, or about 3 mm to about 20 mm.

The inner surface 3032 of the forming device 3030 may include one ormore protrusions (one is shown 3034) extending therefrom. In at leastone embodiment, the forming device 3030 may include two or moreprotrusions 3034 that are circumferentially offset from one anotherabout a central longitudinal axis 3036 through the forming device 3030.The forming device 3030 may include two or more protrusions 3034 whennot shown in the cross-sectional view of FIG. 29. The protrusions 3034may be arranged and designed to deform the can 2920 and optionally theextension portion 2904 of the substrate material 2900 (or a punch) toform one or more reliefs (e.g., reliefs 128-1, 128-2 in FIG. 3) thereinwhen the substrate material 2900) or punch, and the can 2920, arepressed onto the forming device 3030. Recesses or reliefs within theforming device 3030 may be used to define the lobes (e.g., lobes 122-1,122-2 in FIG. 3) in the substrate material 2900. The protrusions 3034may also be arranged and designed to form the solid particulates 2924into a solid mass that also has one or more reliefs therein, and whichgenerally conforms to the deformed shape of the can 2920 and/or thesubstrate material 2900.

FIG. 30 depicts an exploded perspective view of an illustrative pressingassembly 3000 including a forming device 3030, according to one or moreembodiments of the present disclosure. According to some embodiments,the pressing assembly 3030 may include a sleeve 3002, a compressingdevice 3020, and the forming device 3030. The sleeve 3002 may be made ofany suitable material, including a polymer, such as polyurethane, epoxy,polyester, phenolics, other materials, or combinations thereof. In otherembodiments, the sleeve 2003 may be formed of other materials, includingmetals, composites, organic materials (e.g., wood), other materials, orsome combination of the foregoing.

The sleeve 3002 may be generally cylindrical or annular in someembodiments, and may have a bore 3004 formed at least partiallytherethrough. The bore 3004 may include a first diameter portion 3006that transitions to a second, greater diameter portion 3008, as shown inFIG. 30. The first diameter portion 3006 may be sized and shaped toreceive a substrate material 2900 (or punch) and a can 2920 of FIG. 20,and the second diameter portion 3008 may be sized and shaped to receivethe forming device 3030. The substrate material 2900 and can 2920 (seeFIG. 29) may be inserted into the first diameter portion 3006 of thebore 3004, and the forming device 3030 may be inserted into the seconddiameter portion 3008 of the bore 3004. In some embodiments, protrusions3034 (see FIG. 31) of the forming device may extend at least partiallyinto the first diameter portion of the bore 3004. In other embodiments,the protrusions 3034 may be positioned within the second diameterportion 3008 of the bore 3004, and a portion of the substrate may extendinto the second diameter portion 3008 of the bore 3004. In at least oneembodiment, the forming device 3030 may be integral with the sleeve3002.

The compression device 3020 may include a shaft 3022 that is configuredto apply a compression force to the substrate material 2900, which maybe positioned between the shaft 3022 and the forming device 3030. Insome embodiments, the shaft 3022 may be shaped and sized to optionallyfit and/or move within at least a portion of the first diameter portion3006 of the bore 3004 of the sleeve 3002, and to move coaxially and/oralong a longitudinal axis thereof. A shoulder 3024 on the compressiondevice 3020 may limit axial movement with respect to the sleeve 3002.The shoulder 3024 may contact the sleeve 3002 directly, although inother embodiments a ring 3026 disposed between the compression device3020 and the sleeve 3002, may engage the shoulder 3024. In otherembodiments the shoulder 3024 may contact other structures.

FIG. 31 depicts a cross-section side view of the pressing assembly 3000)with the substrate material 2900, solid particulates 2924, and can 2920therein, according to one or more embodiments. In accordance with someembodiments of the present disclosure, the substrate material 2900 maybe positioned within the deformable can 2920, along with the solidparticulates 2924. The compression device 3020 may apply a force to thebase 2902 (see FIG. 29) of the substrate material 2900. The appliedforce may move the substrate material 2900, solid particulates 2924, andthe can 2920 downward toward the forming device 3030. The force exertedby the compression device 3020 may range from about 500 N to about10,000 N. For example, the force may range from about 500 N to about1,000 N, about 1,000 N to about 2,500 N, about 2,500 N to about 5,000 N,or about 5,000) N to about 10,000 N.

The force exerted by the compression device 3020 on the substratematerial 2900 and can 2920 may cause the can 2920, solid particulates2924, and substrate material 2900 to deform into a shape defined by theforming device 3030. The applied force may further cause the solidparticulates 2924 to become a solid mass and press-fit or otherwisebonded to the outer surface 2906 of the extension portion 2904 of thesubstrate material 2900. If the substrate material 2900 is replaced witha punch, the solid particulates 2924 may define a solid mass that isremovable from the punch.

The applied force may cause the protrusions 3034 of the forming device3030 to gouge into and deform the can 2920 and the extension portion2904 of the substrate material 29), thereby forming one or more reliefs(e.g., 128-1, 128-2 in FIG. 3) in the extension portion 2904 of thesubstrate material 2900. The reliefs may also be formed in the mass ofsolid particulates 2924 which may generally conform to the shape of theforming device 3030, the can 2920, the substrate material 2900, or somecombination of the foregoing. In at least one embodiment, a secondsleeve 3040 may be disposed about the sleeve 3002 to help the sleeve3002 maintain rigidity during the pressing process. The second sleeve3040 may be made of a metal or metal alloy material (e.g., steel,tungsten carbide, etc.).

Once pressing is complete, or potentially during pressing, the substratematerial 2900 (and the solid particulates 2924 now coupled thereto) maybe exposed to a high pressure—high temperature (“HPHT”) process. Thesolid particulates 2924 may generally be positioned on the exterior ofthe extension portion 2920 of the substrate material 2900, and may forma layer of diamond crystals or grains. The substrate material 2900 andadjacent layer of solid particulates 2924 may then be sintered under theHPHT conditions. The high pressure and high temperature conditions maycause the solid particulates 2924 (e.g., diamond crystals or grains) tobond to one another to form polycrystalline diamond withdiamond-to-diamond bonds. Additionally, in some embodiments a catalystmay be employed for facilitating formation of the polycrystallinediamond or other layer formed by the solid particulates 2924. In oneexample, a solvent catalyst may be employed for facilitating theformation of a matrix or other layer of solid particulates 2924. Forexample, cobalt, nickel, and iron are some illustrative examples ofsolvent catalysts that may be used in forming polycrystalline diamond.

Within the HPHT process, the pressure may range from about 3 GPa toabout 8 GPa. For example, the pressure may range from about 4 GPa toabout 5 GPa, 4.5 GPa to about 5.5 GPa, 5 GPa to about 6 GPa, 5.5 GPa toabout 6.5 GPa, 6 GPa to about 7 GPa, 6.5 GPa to about 7.5 GPa, or about7 GPa to about 8 GPa. The temperature may range from about 1,200° C. toabout 1,800° C. For example, the temperature may be from about 1,200° C.to about 1,300° C., about 1,300° C. to about 1,400° C., about 1,400° C.to about 1,500° C., about 1,500° C. to about 1,600° C., about 1,600° C.to about 1,700° C., or about 1,700° C. to about 1,800° C. The pressingprocess (e.g., via the pressing assembly 3000) and the HPHT process mayconvert or transform the substrate material 2900 and solid particulates2924 into a shaped cutting insert (e.g., cutting insert 100 in FIG. 3).The time for the HPHT process may range from about 1 minute to about 240minutes in some embodiments. For instance, the solid particulates 2924and substrate material 2900 may be subjected to an HPHT process forbetween about 1 minute and about 10 minutes, between about 10 minutesand about 30 minutes, between about 30 minutes and about 60 minutes,between about 60 minutes and about 120 minutes, or between about 120minutes and about 240 minutes. In an embodiment in which a punchseparate from a substrate material 2900 is used, the punch may beseparated from the solid particulates 2924, which may then be positionedon an already formed substrate material 2900. The substrate material2900 and solid particulates 2924 may then be subjected to the HPHTprocess.

As used herein, the terms “inner” and “outer”; “upper” and “lower”:“upward” and “downward”; “inward” and “outward”; and other like terms asused herein refer to relative positions to one another and are notintended to denote a particular direction or spatial orientation. Theterms “couple,” “coupled,” “connect.” “connection,” “connected,” and thelike refer to both a direct connection and an indirect connection (i.e.,a connection via another element or member.)

Although only a few example embodiments have been described in detailherein, those skilled in the art will readily appreciate that manymodifications are possible in the example implementation withoutmaterially departing from the present disclosure. Accordingly, any suchmodifications are intended to be included in the scope of thisdisclosure. Likewise, while the disclosure herein contains manyspecifics, these specifics should not be construed as limiting the scopeof the disclosure or of any of the appended claims, but merely asproviding information pertinent to one or more specific embodiments thatmay fall within the scope of the disclosure and the appended claims. Anydescribed features from the various embodiments disclosed may beemployed in combination. In addition, other embodiments of the presentdisclosure may also be devised which lie within the scopes of thedisclosure and the appended claims. All additions, deletions andmodifications to the embodiments that fall within the meaning and scopesof the claims are to be embraced by the claims.

In the claims, means-plus-function clauses are intended to cover thestructures described herein as performing the recited function and notonly structural equivalents, but also equivalent structures. Thus,although a nail and a screw may not be structural equivalents in that anail employs a cylindrical surface to secure wooden parts together,whereas a screw employs a helical surface, in the environment offastening wooden parts, a nail and a screw may be equivalent structures.It is the express intention of the applicant not to invoke 35 U.S.C.§112, paragraph 6 for any limitations of any of the claims herein,except for those in which the claim expressly uses the words ‘means for’together with an associated function.

Certain embodiments and features may have been described using a set ofnumerical upper limits and a set of numerical lower limits. It should beappreciated that ranges including the combination of any two values,e.g., the combination of any lower value with any upper value, thecombination of any two lower values, and/or the combination of any twoupper values are contemplated unless otherwise indicated. Certain lowerlimits, upper limits and ranges may appear in one or more claims below.All numerical values are “about” or “approximately” the indicated value,and take into account experimental error and variations that would beexpected by a person having ordinary skill in the art.

What is claimed is:
 1. A method for forming a cutting insert,comprising: inserting a plurality of solid particulates into asubstantially hollow can; inserting a substrate material into thesubstantially hollow can, the substrate material having a base portionand an extension portion; inserting the substantially hollow can,substrate material, and plurality of solid particulates into a bore of asleeve; engaging the substantially hollow can with a forming devicehaving at least one protrusion; and applying a force to the substratematerial within the substantially hollow can, the force causing the atleast one protrusion to deform the substantially hollow can while theplurality of solid particulates and substrate material are therein, theforce further causing the plurality of solid particulates to becomepress-fit to an outer surface of the extension portion while within thesubstantially hollow can.
 2. The method of claim 1, wherein insertingthe plurality of solid particulates is performed prior to inserting thesubstrate material into the substantially hollow.
 3. The method of claim1, wherein inserting the substrate material causes the plurality ofsolid particulates to become positioned between the substrate materialand an interior surface of the deformable can.
 4. The method of claim 1,wherein the substrate material includes a carbide substrate.
 5. Themethod of claim 1, wherein applying the force further causes the atleast one protrusion to deform the extension portion of the substratematerial.
 6. The method of claim 5, wherein applying the force causesthe at least one protrusion to form at least one relief and at least onelobe in the extension portion.
 7. The method of claim 6, furthercomprising: heating the substrate material and plurality of solidparticulates to a temperature between about 1,200° C. and about 1,600°C. after the at least one relief has been formed in the extensionportion.
 8. The method of claim 1, wherein applying the force includesapplying a compressive force using a shaft arranged and designed to fitwithin the bore.
 9. The method of claim 8, wherein the shaft is part ofa compression device, the compression device having a shoulder forrestricting axial movement of the shaft within the bore.
 10. Anapparatus for forming a cutting insert, comprising: a sleeve having abore formed at least partially therethrough, the sleeve being arrangedand designed to receive a substantially hollow can having a plurality ofsolid particulates therein; and a forming device at a first end portionof the bore, the forming device including at least one protrusionextending into the bore, the at least one protrusion being arranged anddesigned to deform the can while the solid particulates are therein. 11.The apparatus of claim 10, further comprising: a compression device at asecond end portion of the bore, the compression device being arrangedand designed to move in a direction parallel to, or coaxial with, acentral longitudinal axis through the bore.
 12. The apparatus of claim11, wherein the compression device and forming device are arranged anddesigned to be positioned within respective portions of the bore havingdiffering sizes.
 13. The apparatus of claim 10, wherein the sleeve ismade of polyurethane, epoxy, polyester, phenolic, or a combinationthereof.
 14. The apparatus of claim 10, wherein the sleeve is a firstsleeve, the apparatus further comprising: a second sleeve at leastpartially enclosing the first sleeve, the second sleeve being more rigidthan the first sleeve.
 15. The apparatus of claim 10, wherein an innersurface of the forming device includes a curved surface having the atleast one protrusion extending therefrom.
 16. The apparatus of claim 15,the curved surface having a radius of curvature from about 3 mm to about20 mm.
 17. The apparatus of claim 10, the at least one protrusionincluding two or more protrusions that are circumferentially offset fromone another about a central longitudinal axis through the formingdevice.
 18. A method for forming a cutting insert, comprising: insertinga plurality of diamond particles into a deformable can; inserting apunch into the deformable can such that the plurality of diamondparticles is between the punch and an interior surface of the can;inserting the punch, the plurality of diamond particles, and thedeformable can at least partially into a compression device, thecompression device including a forming device with at least oneprotrusion; and applying a compressive force to the punch, thecompressive force causing the at least one protrusion to deform the canand the punch, the punch having at least one lobe and at least onerelief formed in a deformed portion thereof, wherein the compressiveforce further causes the plurality of diamond particles to form asubstantially solid layer press-fit to the deformed portion of thepunch.
 19. The method of claim 18, wherein the punch comprises a carbidesubstrate.
 20. The method of claim 19, further comprising: heating thecarbide substrate and the substantially solid layer to a temperaturefrom about 1,200° C. to about 1,600° C.; and exposing the carbidesubstrate and the substantially solid layer to a pressure from about 5GPa to about 7 GPa.
 21. The method of claim 18, wherein applying thecompressive force includes applying a compressive force from about 500 Nto about 10,000 N.